Input. Because you put information in the computer by using it. By moving your mouse, you're telling your computer to move the cursor. Output on the other hand is your computer telling you things. The screen is most obvious output device. read more
Before a computer can process your data, you need some method to input the data into the machine. The device you use will depend on what form this data takes (be it text, sound, artwork, etc.). Similarly, after the computer has processed your data, you often need to produce output of the results. read more
An input device is something that is to input data and instructions into a computer. An output device give you the results, etc. Thank you grade school computer science. So if you look at it carefully, a mouse is used to select, click, drag and drop files, open and close applications, etc.. read more